1. Field of the Invention
The present invention relates to a thin film magnetic head provided, for example, at the trailing side end of a slider facing a magnetic recording medium, and particularly to a thin film magnetic head having an excellent heat radiating property.
2. Description of the Related Art
As shown in FIG. 6, a conventional thin film magnetic head comprises a recording head section h85 provided at the trailing-side end 81a of a slider 81. The recording head section h85 serves as an inductive head comprising a lower core layer 82, an upper core layer 83, and a coil 84 provided between both core layers 82 and 83. In this recording head section h85, a magnetic gap layer 85 is provided between the front ends of the lower and upper core layers 82 and 83, the upper and lower core layers 83 and 82 being magnetically connected to a rear portion. The recording head section h85 is covered with a protective layer 86 made of an insulating material such as Al2O3 or the like.
In a magnetic recording apparatus on which a hard magnetic disk is mounted, when magnetic recording is performed on the magnetic disk serving as a magnetic medium by the recording head section h85, the slider 81 floats with a small distance from the magnetic disk.
In the recording head section h85, a recording current is applied to the coil 84, and a magnetic field induced by the recording current in the lower and upper coil layers 82 and 83 leaks as a leakage magnetic field from the magnetic gap 85 to be applied as a recording magnetic field to the magnetic disk.
In this conventional thin film magnetic head, the temperature of the recording head section h85 increases due to the heat generated from the coil 84, and thus the recording head section h85 thermally expands to project from the surface 81b of the slider 81, which faces the recording medium.
Although the temperature of the recording head section h85 also increases due to an eddy current produced in the lower and upper core layers 82 and 83, the temperature of the recording head section h85 increases mainly due to the heat generated from the coil 84. This is indicated by a graph of FIG. 7 in which the amount of projection from the slider increases as the DC resistance of the coil 84 increases.
Particularly, in a thin film magnetic head capable of high-density recording, the coil 84 generates a large quantity of heat because the recording current supplied to the coil 84 has a high frequency. Therefore, the temperature of the recording head section h85 increases to increase the amount of projection from the facing surface 81b. 
In a magnetic recording apparatus capable of high-density and high-speed recording, the distance between the magnetic medium and the facing surface 81b of the slider 81 is decreased, and thus projection of the recording head section h85 causes a collision of the recording head section h85 with the magnetic medium with high frequency. This highly probably causes a damage to the recording medium and a damage to the recording head section h85.